GB1517342A - Device for reading a record carrier - Google Patents

Device for reading a record carrier

Info

Publication number
GB1517342A
GB1517342A GB19629/75A GB1962975A GB1517342A GB 1517342 A GB1517342 A GB 1517342A GB 19629/75 A GB19629/75 A GB 19629/75A GB 1962975 A GB1962975 A GB 1962975A GB 1517342 A GB1517342 A GB 1517342A
Authority
GB
United Kingdom
Prior art keywords
branch
output
frequency
reading
filter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB19629/75A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Philips Electronics UK Ltd
Original Assignee
Philips Electronic and Associated Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Philips Electronic and Associated Industries Ltd filed Critical Philips Electronic and Associated Industries Ltd
Publication of GB1517342A publication Critical patent/GB1517342A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/14—Digital recording or reproducing using self-clocking codes
    • G11B20/1403—Digital recording or reproducing using self-clocking codes characterised by the use of two levels
    • G11B20/1407—Digital recording or reproducing using self-clocking codes characterised by the use of two levels code representation depending on a single bit, i.e. where a one is always represented by a first code symbol while a zero is always represented by a second code symbol
    • G11B20/1419—Digital recording or reproducing using self-clocking codes characterised by the use of two levels code representation depending on a single bit, i.e. where a one is always represented by a first code symbol while a zero is always represented by a second code symbol to or from biphase level coding, i.e. to or from codes where a one is coded as a transition from a high to a low level during the middle of a bit cell and a zero is encoded as a transition from a low to a high level during the middle of a bit cell or vice versa, e.g. split phase code, Manchester code conversion to or from biphase space or mark coding, i.e. to or from codes where there is a transition at the beginning of every bit cell and a one has no second transition and a zero has a second transition one half of a bit period later or vice versa, e.g. double frequency code, FM code
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/14—Digital recording or reproducing using self-clocking codes
    • G11B20/1403—Digital recording or reproducing using self-clocking codes characterised by the use of two levels

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Digital Magnetic Recording (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)
  • Filters And Equalizers (AREA)

Abstract

1517342 Reading digital data PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 9 May 1975 [13 May 1974] 19629/75 Heading G4C Apparatus for reading self clocking digital data on a carrier includes a differentiating read member and resonant circuit REF2 (Fig. 3) connected to two branch lines, in the first of which is a device having a drooping amplitude/ frequency response curve and in the second of which is a filtering device having a rising amplitude/frequency response curve and a phase characteristic varying with frequency, the outputs of the branch lines being summed to form the output K2. As described the read head HD2 (Fig. 4) which has a coil L1 performing the differentiating function is connected via RC network and amplifier AMP 2 to the base electrode of a transistor Q1 which acts as the branching point, with the low frequency branch being taken from the collector. This branch includes a potentiometer PM (determining the transmission ratio between the branch lines) and capacitor CH forming the filter. The high frequency branch is connected to a bridged T type filter, the output K9 of which is connected via a noise filter C10, C11 and L4 to amplifier Q4 which together with the transistor Q3 in the low frequency branch has its connecter coupled to the output K6.
GB19629/75A 1974-05-13 1975-05-09 Device for reading a record carrier Expired GB1517342A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7406380A NL7406380A (en) 1974-05-13 1974-05-13 DEVICE FOR READING A MAGNETIZED INFORMATION CARRIER.

Publications (1)

Publication Number Publication Date
GB1517342A true GB1517342A (en) 1978-07-12

Family

ID=19821339

Family Applications (1)

Application Number Title Priority Date Filing Date
GB19629/75A Expired GB1517342A (en) 1974-05-13 1975-05-09 Device for reading a record carrier

Country Status (7)

Country Link
US (1) US3996614A (en)
JP (1) JPS552645B2 (en)
DE (1) DE2518983A1 (en)
FR (1) FR2271630A1 (en)
GB (1) GB1517342A (en)
IT (1) IT1037991B (en)
NL (1) NL7406380A (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53125721A (en) * 1977-04-08 1978-11-02 Matsushita Electric Ind Co Ltd Video receiver
US4323932A (en) * 1979-07-30 1982-04-06 Sperry Corporation Readback pulse compensator
US4244008A (en) * 1979-07-30 1981-01-06 Siemens Corporation Read back compensation circuit for a magnetic recording device
ZA81781B (en) * 1980-02-13 1982-03-31 Int Computers Ltd Digital systems
EP0059559A1 (en) * 1981-02-20 1982-09-08 Elcomatic Limited Improvements in digital magnet recording
US4635140A (en) * 1982-05-08 1987-01-06 Victor Company Of Japan, Limited Digital recording/playback system with limited frequency range
JPH0619808B2 (en) * 1985-07-03 1994-03-16 アルプス電気株式会社 Magnetic recording / reproducing device
JPS628305A (en) * 1985-07-03 1987-01-16 Alps Electric Co Ltd Magnetic recording and reproducing device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711843A (en) * 1970-04-27 1973-01-16 Olivetti & Co Spa Self-adapting synchronization system for reading information from a moving support
JPS5143367B2 (en) * 1972-07-07 1976-11-20

Also Published As

Publication number Publication date
US3996614A (en) 1976-12-07
FR2271630A1 (en) 1975-12-12
NL7406380A (en) 1975-11-17
JPS552645B2 (en) 1980-01-21
DE2518983A1 (en) 1975-12-04
IT1037991B (en) 1979-11-20
JPS50156410A (en) 1975-12-17

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee